1. Field of the Invention
The present invention relates to a displaying technology of a tumor nutrient blood-flow in imaging of a tumor performed by using a contrast medium.
2. Description of the Related Art
Recently, a microbubble ultrasonic contrast medium for intravenous injection of which microbubbles enhance echo reflection has been commercially manufactured, and a contrast echo method has been performed. According to this method, a blood-flow signal can be enhanced with microbubbles introduced in a blood vessel, and blood-flow dynamic states can be clearly observed. Moreover, microbubbles have a characteristic that they are specifically englobed by Kupffer cells in a liver, thereby being expected to be effective in a field of hepatic tumor diagnosis.
According to the contrast echo method, observed images largely vary depending on a time phase for imaging. In other words, in an artery phase that appears after over ten seconds from an intravenous injection, an image with an enhanced artery blood flow is obtained. On the other hand, in a late phase that appears after a few minutes from the intravenous injection, hepatic parenchyma is enhanced as microbubbles are captured in Kupffer cells, consequently, a tumor in which Kupffer cells decrease to fewer than those in normal tissues gives a low signal, so that an image on which a tumor form is recognized can be obtained.
Recently, a contrast medium called a next-generation contrast medium has appeared with which long-time imaging can be achieved at a low sound pressure. One of the next-generation contrast mediums was approved in December 2006 in Japan, and its clinical application has been progressing.
Regarding the contrast echo method, developments are made in a technology of displaying an elapse time from an injection of a contrast medium into a subject, and a technology of additionally displaying the number of doses for indicating which dose of the contrast medium an elapse time corresponds to (for example, see JP-A 2007-301005 (KOKAI)).
To diagnose a tumor, presence and dynamic states of an artery that provides nutrition to the tumor are important, so that image diagnosis needs to be performed by combining an image in the artery phase and an image in the late phase. However, any method that can display such combination effectively has not been provided.